Detection of an antioxidant profile in the human brain in vivo via double editing with MEGA-PRESS
Detection of an antioxidant profile in the human brain in vivo via double editing with MEGA-PRESS
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DOI：
10.1002/mrm.21086
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发表时间：
2006-12-01
影响因子：
3.3
通讯作者：
Gruetter, Rolf
中科院分区：
文献类型：
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作者：
Terpstra, Melissa;Marjanska, Malgorzata;Gruetter, Rolf
维生素C(抗坏血酸)和谷胱甘肽(GSH)是人类大脑中浓度最高的两种非酶类抗氧化剂。在这项研究中，设计了在4T的(露水)巨型印刷机上进行双重编辑，以在相同的时间内测量两种抗氧化剂，而以前测量一种抗氧化剂所需的时间相同。在四名受试者的枕叶中，用Dew Mega Press重复且同时检测到分辨抗坏血酸(ASC)和GSH共振。用露珠压谱的LC模型分析测得天冬氨酸和谷胱甘肽的浓度分别为0.8+/-0.1和1.0+/-0.1mU/g(均值+/-SD)，平均Cramer-Rao下限分别为10%和7%。除了在相同回声时间(TE)的J调制的影响外，双重编辑不会影响灵敏度。为了确定氧化形式的ASC和GSH在体内对露珠压力谱的贡献程度，在生理pH和温度下测量了脱氢抗坏血酸(DHA)和氧化谷胱甘肽(GSSG)的化学位移和偶合常数。DHA对3.73ppm露珠压力机ASC的共振没有贡献。在生理条件下，GSSG对露珠高压GSH共振(3.0ppm)的贡献可以忽略不计，在异常高的浓度下，GSSG共振(3.3ppm)将证明这一贡献。
Vitamin C (ascorbate) and glutathione (GSH) are the two most concentrated non-enzymatic antioxidants in the human brain. Double editing with (DEW) MEGA-PRESS at 4T was designed in this study to measure both antioxidants in the same amount of time previously required to measure one. In the occipital lobe of four human subjects, resolved ascorbate (Asc) and GSH resonances were detected repeatedly and simultaneously using DEW MEGA-PRESS. The Asc and GSH concentrations measured using LCModel analysis of DEW MEGA-PRESS spectra were 0.8 +/- 0.1 and 1.0 +/- 0.1 mu mol/g (mean +/- SD), with average Cramer-Rao lower bounds (CRLB) of 10% and 7%, respectively. Aside from the effects of J-modulation at a common echo time (TE), double editing did not compromise sensitivity. To determine the extent to which the oxidized forms of Asc and GSH contribute to DEW MEGA-PRESS spectra in vivo, chemical shifts and coupling constants for dehydroascorbate (DHA) and oxidized glutathione (GSSG) were measured at physiologic pH and temperature. DHA does not contribute to the 3.73 ppm DEW MEGA-PRESS Asc resonance. GSSG contributions to the DEW MEGA-PRESS GSH resonance (3.0 ppm) are negligible under physiologic conditions, and would be evidenced by a distinct GSSG resonance (3.3 ppm) at exceptionally high concentrations.